One-Pot Synthesis of Fatty Amines: Rh-Catalyzed Hydroaminomethylation of 1-Decene in an Aqueous Microemulsion System—Influence of Reaction Conditions on the Reaction Performance

Round 1

Reviewer 1 Report

The manuscript "One-Pot Synthesis of Fatty Amines: Rh-Catalyzed Hydroaminomethylation of 1-Decene in an Aqueous Microemulsion System - Influence of Reaction Conditions on the Reaction Performance" is an excellent study on this important reaction. I must say that I rarely see studies that are designed and executed in such fantastic manner and described in a very clear way. It's definitely a work worth publishing in catalyst as the authors performed a large number of reaction under changing conditions, to figure out the relationships between various parameters and reaction yield. One small addition I would welcome is an additional figure (or an addition to figure 1) with a schematic representation of the Rh catalyst precursors for readers, who don't immediately know how Rh(cod) catalysts look like. Apart from that I don't have any comments.

Author Response

Dear Reviewer 1,

Thank you for your kind assessment. We added the structure of the precursor Rh(acac)(cod) and the formation of the active catalyst species with the ligand SX and synthesis gas in Figure 1. (Page 2)

Reviewer 2 Report

The authors performed the Hydroaminomethylation of the 1-decene and diethylamine using Rh(acac)(cod)/SulfoXantphos catalyst complex . Effects of reaction  temperature, pressure, catalyst ligands and so on were investigated, and  a relatively high cativity and selectivities  were observed. This work presents some novel results for hydroaminomethylation of long chain olefins and is suggested to publish in Catalysts after a minor revision.

This manuscript presented the  relations between the reaction conditions and the conversion/selectivities, which are the catalytic results. However, they failed to discuss the reason. 

title: what is reaction performance? catalytic performance of the homogeneous catalyst, or the reactivity of the substrate 1-decene.

L101-102:"The aqueous catalyst phase (including the surfactant) was removed by 102 syringe and transferred to the reactor." the temperature  and duration should be described. Is there any loss of ctalyst?

Author Response

Dear Reviewer 2,

Based on your comments, we revised our manuscript in some places. We added the advantage of catalyst recycling of multiphase systems and its meaning for industrial applications. This clarifies the added value of this work and presents the reason for the necessary research. ( see page 1, bottom)

We included the following paragraph:

These multiphase systems are more attractive than conventional homogeneous solvents because of the comparatively simple possibility of catalyst recycling. In microemulsion systems, the catalyst and products are ideally in different phases after a successful reaction, which can be separated from each other. This offers enormous advantages for continuous operation in the industrial processes concerning the reuse of expensive metal catalysts, such as rhodium.

 

Also, we have defined the term "reaction performance" and our idea of it more precisely. (see page 2, top)

 In section 3.4 we mentioned recycling and the appropriate temperatures for phase separation. This section is now also already mentioned in the experimental section 2.3. Since recycling experiments did not lead to the desired result, the catalyst loss was not determined further. Based on our work on hydroformylation and reductive amination, we assume that leaching occurs in similar orders of magnitude. Furthermore, recycling and leaching are part of current ongoing research. (see page 10)

We included the following sentence:

Based on these observations, leaching experiments of the catalyst were not performed. From our HF and RA results we know, that Rh leaching from microemulsion systems is very low(below one ppm). Due to comparable reaction conditions, the catalyst leaching for the HAM should be similar or in the same order of magnitude.

Reviewer 3 Report

Please see the pdf file attached.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer 3,

Thank you for your comments and hints to improve our manuscript. We restructured the paragraph about the chemo- and regioselectivity and clarified the definition of the aldehyde yield. Since branched amines could not be observed, they are not included in our equations. The introduction paragraph was restructured too. The aims of our work are described in a continuous paragraph for a better reading flow. Additionally, we have fully implemented your suggestion on rephrasing and thus adjusted it to the wording of  Table 1.